@malmi I also use up north and, if in Northern Ireland and going down to Dublin, down south. I don't change the name of the country to Southern Ireland. No Irish people do.
If you take my point on Ukraine/Russia then that's the end of the discussion really, I've explained to you why Irish people find it offensive and you've agreed that you understand.
Me using North Korea instead of DPR Korea is not the same as (1) I did not realise until this thread that people from DPRK refer to DPRK and not North Korea or that they find North Korea offensive (2) In this knowledge, should I ever meet someone from DPRK whom I didn't wish to offend I would be conscious of this issue and would not just barrel in demanding to call it something I know he/she finds offensive for my convenience (3) I do not live right beside DPRK so my ignorance could be excused and (4) most importantly, this is not a situation where a chunk has been taken out of DPRK's original country by force by my country (which would surely place an onus on me to show some respect in how I refer to the country rather than attempting, arrogantly, to rename the remainder of the country for my convenience).
And whereas it's a lesser point, the geographical issues are relevant also. You calling Ireland "Southern Ireland" is implying that it is equivalent to Northern Ireland, ie that Britain has left only half of the country to the Irish rather than 85%. We are not half a country. And saying that there is one point that is more northerly in ROK than in DPRK or whatever is silly - of course you're not going to get an absolutely linear north-south split unless you have millions of builders in using spirit levels. That's totally distinguishable from a situation in which you are calling a country with the most northerly point on an island "Southern Ireland".
You really haven't proved your point by calling Sudan North Sudan. That's you making the same error again, and unless you consider yourself the ultimate arbiter of reasonableness, this means nothing except that your knowledge of Africa is as good as my knowledge of east Asia (not very).